Excessive daytime sleepiness, hallucinations and REM sleep behavior disorder are symptoms reported in both dementia with Lewy bodies (DLB) and narcolepsy. Considering the demonstration of low hypocretin-1/orexin A levels in the cerebrospinal fluid (CSF) of most patients with narcolepsy, we hypothesized the presence of a deficient hypocretinergic transmission in DLB. Hypocretin-1 was tested in the CSF of 10 DLB patients. Levels were found to be in the normal range (mean 521 pg/ml, range 382-667) when compared to controls (n = 20, mean 497 pg/ml, range 350-603) and Alzheimer's disease patients (n = 7, mean 474 pg/ml, range 333-564). In DLB, excessive daytime sleepiness, hallucinations and REM sleep behavior may occur in the absence of a detectable hypocretin deficiency.
2004 S. Karger AG, Basel